A group of US Special Forces troops were caught close to the action in Syria when Turkey shelled Kurdish positions in the area, a report said Friday.

A senior Pentagon official told Newsweek that the attack by the Turkish forces was so heavy that the US personnel considered firing back in self-defense but ultimately withheld their fire.

Newsweek learned from an Iraqi Kurdish intelligence official and the senior Pentagon official that Special Forces operating on Mashtenour hill in the Kurdish city of Kobani were not far from heavy artillery fire from Turkish forces, who they are trying to evict from the border area.

Apparently no US troops were injured.

Instead of firing back, the Special Forces withdrew once the shelling had ceased, the website reported.

Meanwhile, Turkey ramped up its air and artillery strikes in northeast Syria on Friday, escalating an offensive against Kurdish militia that has drawn warnings of a humanitarian catastrophe and threats of sanctions from US President Donald Trump.